Cephalochordata
noun plural
Ceph·a·lo·chor·da·ta
| \ -ˌkȯr-ˈdät-ə
, -ˈdāt-ə
\
, -ˈdāt-ə
\
Medical Definition of Cephalochordata
: a subphylum or other major taxon of the phylum Chordata comprising the lancelets and characterized by extension of the notochord to the anterior as well as to the posterior end of the body